With Safari (macrumors forum) open in one window and the Twitter app open in a small window, I get incredible stuttering when slowly scrolling through Twitter. My iPhone 6S Plus does not stutter in this way. I've also noticed other stuttering occurring at random times. I'm not even doing anything intensive; only basic browsing and looking at photos, etc. Is anyone else having this issue? Please try it and let me know. I hope this can be fixed in a software update, as I love the new iPad Pro other than this problem!